Polygamy: Polygyny and Polyandry

Polygamy is plural marriage including Polygyny which is the marriage of one man to several women and Polyandry which is the marriage of one woman to several men.
Different factors in different societies have bearing on the practice of Polygyny. In societies in which women are economically important, Polygyny favours increase in man's wealth and consequent social position. In ancient and medieval India, many rulers married women from different clans and villages to strengthen their political, social and economic position.
Polygyny is characteristically found in societies with high productivity where agriculture is labour intensive and so additional women in the household is an advantage. Even in societies in which Polygyny is defined few men have more than one wife.
In Sororal Polygyny, a man marries sisters who may cooperate and get along without creating family discord.
Polyandry has been recorded in parts of Tibet and among the Todas and Paharis in India. Polyandry may be an adaption arising out of shortage of women in some societies. The shortage may be due to female infanticide. In societies where men may have to be away from home for long spells of time a woman with more than a husband is assured of protection and help. Fraternal Polyandry recorded in the Toda tribes in the Nilgiri hills, South India is a system according to which a woman marries brothers. Usually the eldest brother becomes the legal father to the child born to the woman. Occasionally, a woman may marry men who are not biologically brothers. Todas have become largely monogamous.